The Clinical Core is organized to provide the clinical samples for all 4 projects. The core will have 4 functions: 1) to recruit and amange patients for the 3 protocols supporting the 4 projects, 2) to collect, process and catalogue all tissues (blood, lymph node, and GALT), 3) to assist the Administrative Core with tissue shipping and management of regulatory issues related to protocol administration, and 4) to maintain all patient and clinical laboratory records in a case report form and enter data into the established data base. Patients will be followed in the NIH funded General Clinical Research Center where all blood will be drawn and patients will receive required pre and post operative care. Tissues will receive initial processing through the clinical core and appropriate samples will be packed and shipped to off-site investigators. In addition, all clinical information (status, medications, clinical laboratory measures like CD4 and HIV viral load) will be maintained in a patient chart and entered into a central database by the nurse manager. Over the course of these projects we will recruit 70 individuals into 3 protocols that require lymph node and colon biopsy. We present data to show this goal is within the scope of recent accomplishments by our group. Protocol A will support Hypothesis 1 and distribute tissues to investigators in Projects 1, 2, and 4. Protocol B will support Hypothesis 2 and will distribute tissues to investigators in all 4 projects, and Protocol C will support Hypothesis 3 and distribute tissues to investigators in Projects 1, 2, and 4.